The AAV7 or Amphibious
Assault Vehicle in it's nature is an armored personnel carrier, intended
to deliver troops from the landing ships to attack the beachheads and
support them with it's own firepower. It entered service in early 1970s,
but until 1985 it was known as the LVTP7.

AAV design evolved before the World War II with the introduction of the
Roebling Alligator
in 1932 after a development process which took 7 years. However, the
initial Alligators didn't give an impressive performance, so in 1940,
Roebling introduced another model, called the Crocodile. The Croc had a
road speed of 40 km/h and moved on water with a maximum speed of 15
km/h. The LVT-1, introduced in 1941-43, was a complete copy of the
Crocodile, except that it was made of steel rather than aluminum.

The AAV7s amphibious
assault vehicles carry troops from ship to shore along with supplies and
provide avenues for a forced entry into the semi aquatic assault areas.
Some of these vehicles tasks also include guarding the checkpoints,
patrolling and escorting convoys. It can transport up to 25 fully
equipped troops. Vehicle's internal volume and cargo capacity allows it
to be used as an expedient ambulance or a refueler during the war.
Arguably, the AAV7A1 is the most versatile armored vehicle belonging to
the Marine Corps.

Usually AAVs are armed
with one 12.7-mm (0.50) caliber machine gun. New and improved vehicles
have a dual setup of one 40-mm grenade launcher and one 12.7-mm HMV
heavy machine gun.

The Marine Corps upgraded 64% of the fleet
of these vehicles by putting them through reliability, maintainability
(RAM) and availability improvement. Despite that it is expected to be
replaced by the Expeditionary Fighting Vehicle starting from 2008.